Field of Technology
Embodiments of the invention relate to a touch sensor integrated type display device.
Discussion of the Related Art
In recent years, various input devices, such as a keyboard, a mouse, a track ball, a joystick, and a digitizer, have been used to allow users to interface with home appliances or information telecommunication devices. However, when the user makes use of these input devices, the user's dissatisfaction with the input devices increase because the user is required to learn how to use the input devices and the input devices occupy space. Thus, a demand for a convenient and simple input device capable of reducing erroneous operations is increasing. In response to the demand, a touch sensor was proposed to recognize information when the user inputs the information by directly touching the screen with his or her hand or a pen.
The touch sensor has a simple configuration capable of reducing the erroneous operations. The user can also perform an input action without using a separate input device and can quickly and easily manipulate a display device through the contents displayed on the screen. Thus, the touch sensor has been applied to various display devices.
The touch sensor used in the display device may be classified into an add-on type touch sensor, an on-cell type touch sensor, and an integrated type (or in-cell type) touch sensor depending on its structure. The add-on type touch sensor is configured such that the display device and a touch sensor module including the touch sensor are individually manufactured and then the touch sensor module is attached to an upper substrate of the display device. The on-cell type touch sensor is configured such that elements constituting the touch sensor are directly formed on the surface of an upper glass substrate of the display device. The in-cell type touch sensor is configured such that elements constituting the touch sensor are mounted inside the display device to thereby achieve a thin profile of the display device and increase the durability of the display device.
Among the above touch sensors, because the in-cell type touch sensor may share a common electrode of the display device as a touch electrode, a thickness of the display device may decrease as compared to the other type of touch sensors. Further, because the touch elements of the in-cell type touch sensor are formed inside the display device, the durability of the display device may increase. Hence, the in-cell type touch sensor has been widely used.
The in-cell type touch sensor can solve the problems generated in the add-on type touch sensor and the on-cell type touch sensor because of the advantages of the thin profile and the improvement in durability. The in-cell type touch sensor may be divided into a light type touch sensor and a capacitive touch sensor depending on a method for sensing a touched portion. The capacitive touch sensor may be subdivided into a self capacitive touch sensor and a mutual capacitive touch sensor.
The self capacitive touch sensor forms a plurality of independent patterns in a touch area of a touch sensing panel and measures changes in a capacitance of each independent pattern, thereby deciding whether or not a touch operation is performed. The mutual capacitive touch sensor crosses X-axis electrode lines (for example, driving electrode lines) and Y-axis electrode lines (for example, sensing electrode lines) in a touch/common electrode formation area of a touch sensing panel to form a matrix, applies a driving pulse to the X-axis electrode lines, and senses changes in voltages generated in sensing nodes defined as crossings of the X-axis electrode lines and the Y-axis electrode lines through the Y-axis electrode lines, thereby deciding whether or not a touch operation is performed.
In the mutual capacitive touch sensor, a mutual capacitance generated in touch recognition of the mutual capacitive touch sensor is very small, but a parasitic capacitance between a gate line and a data line constituting the display device is very large. Therefore, it is difficult to accurately recognize a touch position because of the parasitic capacitance.
Further, because a plurality of touch driving lines for a touch driving mode and a plurality of touch sensing lines for a touch sensing have to be formed on the common electrode for the multi-touch recognition of the mutual capacitive touch sensor, the mutual capacitive touch sensor requires a very complex line structure.
On the other hand, because the self capacitive touch sensor has a simpler wiring structure than the mutual capacitive touch sensor, touch accuracy of the self capacitive touch sensor may increase. Hence, the self capacitive touch sensor has been widely used, if necessary or desired.
A related art touch sensor integrated type display device is described below with reference to FIGS. 1 and 2. FIG. 1 is a plane view of a related art touch sensor integrated type display device, and FIG. 2 is a plane view showing a touch sensing location obtained by the touch sensor integrated type display device shown in FIG. 1.
Referring to FIG. 1, the related art touch sensor integrated type display device includes an active area AA, in which touch/common electrodes T11-T1a, T21-T2a, T31-T3a, T41-T4a, T51-T5a, T61-T6a, T71-T7a, and T81-T8a are disposed and data is displayed, and a bezel area BA positioned outside the active area AA. In the bezel area BA, various wires and a source and touch driving integrated circuit (IC) 10 are disposed.
The active area AA includes the plurality of touch/common electrodes T11-T1a, T21-T2a, T31-T3a, T41-T4a, T51-T5a, T61-T6a, T71-T7a, and T81-T8a divided in a first direction (for example, x-axis direction) and a second direction (for example, y-axis direction) crossing the first direction and a plurality of touch/common routing wires W11-W81, W12-W82, W13-W83, W14-W84, W15-W85, W16-W86, W17-W87, W18-W88, W19-W89, and W1a-W8a, which are respectively connected to the plurality of touch/common electrodes T11-T1a, T21-T2a, T31-T3a, T41-T4a, T51-T5a, T61-T6a, T71-T7a, and T81-T8a and are arranged in the second direction.
The plurality of touch/common electrodes T11-T11a, T21-T2a, T31-T3a, T41-T4a, T51-T5a, T61-T6a, T71-T7a, and T81-T8a in the active area AA are formed by dividing a common electrode of the display device, and thus operate as common electrodes in a display driving mode for displaying data and operate as touch electrodes in a touch driving mode for recognizing a touch location.
The bezel area BA positioned outside the active area AA includes the source and touch driving IC 10 and various wires. In the display driving mode, the source and touch driving IC 10 supplies display data to data lines (not shown) in synchronization with a drive of gate lines (not shown) of the display device and supplies a common voltage to the touch/common electrodes (or the common electrodes). In the touch driving mode, the source and touch driving IC 10 supplies a touch driving voltage to the touch/common electrodes and scans a change in a capacitance of each touch/common electrode before and after a touch operation, thereby calculating a touch location, at which the touch operation is performed. The various wires include the touch/common routing wires W11-W81, W12-W82, W13-W83, W14-W84, W15-W85, W16-W86, W17-W87, W18-W88, W19-W89, and W1a-W8a connected to the touch/common electrodes T11-T1a, T21-T2a, T31-T3a, T41-T4a, T51-T5a, T61-T6a, T71-T7a, and T81-T8a, the gate lines connected to the source and touch driving IC 10, the data lines, and the like.
Referring to FIG. 2, the touch/common electrodes T11-T1a, T21-T2a, T31-T3a, T41-T4a, T51-T5a, T61-T6a, T71-T7a, and T81-T8a respectively have touch sensing nodes S11-S1a, S21-S2a, S31-S3a, S41-S4a, S51-S5a, S61-S6a, S71-S7a, and S81-S8a, which are recognized as the touch location when the touch operation is performed.
The above-described related art touch sensor integrated type display device is configured so that the size of one touch/common electrode corresponds to the size of dozens of pixel electrodes and the touch/common electrodes are respectively connected to the touch/common routing wires. The number of touch/common electrodes is obtained by multiplying the number of touch/common electrodes positioned on one row and the number of touch/common electrodes positioned on one column. With a recent trend toward the large-sized display device, the display device becomes larger and larger and thus the number of touch/common electrodes sharply increases. When the number of touch/common electrodes sharply increases with the recent trend toward the large-sized display device as described above, the number of touch/common routing wires connected to the touch/common electrodes positioned on one column becomes more than the number of pixel electrodes positioned on one row in an area corresponding to each touch/common electrode. Hence, the touch/common routing wire not overlapping the data line results and thus an aperture ratio of the display device is reduced.
Further, when the touch/common routing wire is not connected to some of the touch/common electrodes so as to prevent the reduction of the aperture ratio, a touch location cannot be accurately recognized when the touch operation is performed on the touch/common electrode, to which the touch/common routing wire is not connected. Thus, there is a limit to the size of the display device, to which the related art touch sensor integrated type display device can be applied. Further, the number of channels of the source and touch driving IC 10 connected to the touch/common electrodes increases due to an increase in the number of touch/common routing wires, and thus the size of the readout integrated circuit increases. Hence, the manufacturing cost of the display device increases.